Methods of bonding semiconductor elements and lead frames (supporting members) during production of semiconductor devices include methods wherein a filler such as silver powder is dispersed in a resin such as an epoxy-based resin or polyimide-based resin to form a paste (for example, silver paste), which is used as a bonding agent. In this method, a dispenser, printer, stamping machine or the like is used to coat the adhesive paste onto the die pad of a lead frame, and then the semiconductor element is subjected to die bonding and heat cured for bonding to produce a semiconductor device.
With increasing speeds and higher integration of semiconductor elements in recent years, there has been demand for high heat dissipating properties to ensure operating stability for semiconductor devices.
As means for achieving higher heat dissipation than with conventional conductive adhesives having contact between metallic particles, there have been proposed adhesive compositions in which silver particles with high thermal conductivity are filled to a high degree (Patent Literatures 1 to 3), an adhesive composition using solder particles (Patent Literature 4), and an adhesive composition using highly sinterable metal nanoparticles with mean particle diameters of no greater than 0.1 μm (Patent Literature 5).
In addition, there has been proposed an adhesive composition employing special surface-treated microsize silver particles, having thermal conductivity and high-temperature connection reliability superior to these compositions, whereby the silver particles become sintered together by heating at from 100° C. to 400° C. (Patent Literature 6). In the adhesive composition proposed in Patent Literature 6 where silver particles are sintered together, presumably the superior thermal conductivity and high-temperature connection reliability compared to other methods is due to formation of metal bonding by the silver particles.